I'd like to see a new type of resource in the game: illicit resources. They have the potential to harm your rivals while gaining you a quick buck (i.e. selling opium under the nose of the Chinese, thus crippling their productivity), but must be carefully utilized, becuase it's not good for relations (and may start the Opium War, which China kind of lost, but still).
I know it's a little creepy, but nations have used this type of tactic in the past, and Civ 4 would be more realistic with it.
I know it's a little creepy, but nations have used this type of tactic in the past, and Civ 4 would be more realistic with it.